PACKAKP.] GEOGRAPHICAL DISTRIBUTION OF PHYLLOPODA. 365 



SO that to liim is due the credit of first distinguisMng the Central prov- 

 ince. 



In 1866, Professor Baird,^ from a study of the avifauna of the United 

 States, conckided that " the ornithological provinces of North America 

 consist of two great divisions of nearly equal size in the United States, 

 meeting in the vicinity of the one hundredth meridian, the western half 

 divisible again into two, more closely related to each other than to the 

 eastern, though each has special characters. These three sections form 

 tbree great provinces to be known as the western, middle, and eastern ; 

 or those of the Pacific slope; of the great bashi, the Eocky Mountains 

 and the adjacent plains; and of the fertile plains and region generally, 

 east of the Missouri." 



In 1871, Mr. -J. A. AUen^ divided the avifauna of the United States 

 into two provinces, the eastern and western, the latter embracing the 

 Pacific coast. Mr. Allen afterwards adopted Professor Baird's division 

 into three provinces. (The geographical distribution of the mammalia, 

 etc. Bulletin of Haydeu's U. S. Geographical and Geological Survey 

 of the Territories, May 3, 1878.) 



In 1873,^ Mr. VV. G. Binney published a map of the distribution of 

 our land shells, dividing the molluscan fauna into the Eastern, Central, 

 and Pacific i^rovinces. 



In 1875, Prof. E. D. Cope, in his check-list of IsTorth American Batra- 

 chia and Eeptilia,* divided the Nearctic realm of Sclater into the Aus- 

 troriparian. Eastern, Central, Pacific, Sonoran, and Lower Californian 

 regions. He remarks that "the Pacific region is nearly related to the 

 Central, and, as it consists of only the narrow district west of the Sierra 

 ISTevada, might be regarded as a subdivision of it. It, however, lacks 

 the mammalian genera Bos and Antilocapra, and possesses certain pecu- 

 liar genera of birds, as Geococcyx, Ghamcea, and Oreortyx. . . . There 

 are some genera of reptiles, e. g. Gharina, related to the Boas, Lodia, 

 Aniella, Gerrhonotus, and Xantusia, which do not occur in the central 

 subregion. There are three characteristic genera of Batrachia, all 

 Salamanders, viz : Anaides, Batrachoseps, and Bicamptodon ; while the 

 eastern genera Plethodon and Biemyctylus reappear after skipping the 

 entire central district." Cope adds that "the fresh- water fish fauna is 

 much like that of the central district in being poor in types." Cope's 

 Sonoran region is evidently a northward extension of the Central Ameri- 

 can fauna, which sends its outliers into Southern Arizona, Utah, and 

 New Mexico, and is not to be taken into account in discussing the faunal 

 provinces of the United States alone. 



In 1876, Wallace, in his "Geographical Distribution of Animals," di- 

 vided the Nearctic region into four subregions, viz : the Californian, 

 Central or Eocky Mountain, Alleghanian, and Canadian. His Central 

 subregion extended to lat. 25° N. 



It will be seen from this review that by general consent the fauna of 

 the Pacific slope is on the whole regarded as belonging to a separate 

 province from that of the Eocky Mountain plateau, w^hether we regard 

 the mammals, birds, reptiles, amphibians, Coleoptera, or land shells. 



Botanically, as observed by those who have traveled across the plains 

 to California, the flora of the great plains is quite different from that of 

 the Eastern States, and the Pacific flora is as distinct from the central 

 flora. This has been clearly shown by Sir J. D. Hooker and Prof. Asa 



* American Journal of Science and Arts, January and March, 1866. 



* Bulletin of the Museum of Comp. Zoology, April, 1871. 



3 Catalogue of the Terrestrial Molluscs of North America. Bull. Mus. Comp. Zool., 

 1873. 

 ^BuUetin U. S. Nat. Mas., Washington, 1875. 



